septet vs musical organisation

septet and musical organisation both are nouns.

Word	Noun	Adjective	Verb	Adverb
septet	Yes	No	No	No
musical organisation	Yes	No	No	No

As nouns, musical organisation is a hypernym of septet; that is, musical organisation is a word with a broader meaning than septet:

Other hypernyms of septet include musical group, musical organization.

septet (noun)	musical organisation (noun)
a musical composition written for seven performers	an organization of musicians who perform together
seven people considered as a unit
a set of seven similar things considered as a unit
seven performers or singers who perform together
the cardinal number that is the sum of six and one